The present invention relates to a heat exchanger, such as a heat exchanger used in a beverage dispenser, and particularly to a heat exchanger that uses ice to cool components for beverages dispensed by the beverage dispenser. The invention also relates to an improved beverage dispenser utilizing a heat exchanger, methods of cooling beverages and beverage components, and methods of constructing a heat exchanger.
Many consumers desire cold beverages. As a result, beverage dispensers have been developed that have a variety of different ways of cooling the beverage or its components, such as carbonated water and a syrup concentrate, before the beverage is dispensed. Some dispensers have a refrigeration system, including a compressor and evaporator, to cool the beverage. One class of dispensers rely on melting ice contained in an ice bin to cool the beverage components. An example of such a dispenser is disclosed in U.S. Pat. No. 5,397,032. This class of dispensers will also often be equipped with an ice dispenser, so that customers who wish to have ice in their beverages can conveniently dispense ice from the ice bin into their beverage cup. Such an ice and beverage dispenser is disclosed in U.S. Pat. No. 6,880,358.
In this class of machines, a typical dispenser will have a heat exchanger in the form of a cold plate located at the bottom of an ice bin. Ice in contact with the cold plate melts to keep the cold plate cooled. Ice is added to the ice bin to replace that which melts. The ice can be added in a manual operation, being hauled to the dispenser from an ice storage bin located elsewhere in the facility, or an automatic ice making machine can be positioned over the dispenser so that ice formed by the ice machine falls into the dispenser ice bin to keep it full. U.S. Pat. No. 6,761,036 discloses a beverage dispenser with an integral ice maker.
The cold plate typically comprises a coil basket made of several stainless steel tubes embedded in a block of aluminum. The aluminum provides a good heat transfer between the melting ice and the fluids carried in the tubing in the cold plate. The cold plate has a surface shaped to allow for drainage of the melting water. U.S. Pat. No. 5,484,015 discloses such a cold plate type of heat exchanger.
While this type of heat exchanger has seen wide spread usage and performs very well, there have been attempts to find other ways to cool beverage components in a beverage dispenser using ice as the cooling medium, perhaps because of the cost and weight of a typical aluminum cold plate. For example, see U.S. Pat. No. 5,950,866. However, such devices have not gained widespread acceptability. Thus there is still a need for a heat exchanger that weighs less and costs less than an aluminum block type of cold plate for use in a beverage dispenser. Each of the above listed patents is hereby incorporated by reference.